12 volt battery

The car was very low on gas. But the latest findings are even stranger. We have been told that the alcohol content was too high. It was somewhere between 10%-12%. The tech told my wife that an average car would run on that ok but not the Prius. Is there any info about fuel content in the Toyota literature?
Do they issue a test kit to check the gas before I fill up? I'm sure that would be a very big selling point.
I'm upset because we have been told this visit is not covered by our warranty , again the car is only seven weeks old.
Has anyone hear of this problem?
I don't even know if this is the spot to post this?

 

Frankly, the tech who told you the Prius can't take 10% ethanol is an idiot.

The Prius is designed to handle gasoline with up to 15% ethanol no problems-- It's in your owner's manual.

The Prius is designed that way because virtually ALL major cities in the U.S. have local laws that require gasoline sold in their jurisdictions to contain 10% ethanol as an oxygenate to cut down on smog emissions.

 

The dealer is full of it. I believe you would have a very hard time finding gas without 10% alcohol in the US. Check the fuel specs in the owners manual. If you can't speak with someone in authority at the dealer it's time to talk to Toyota. Try calling from the dealership in front of prospective buyers.

 

Today my 2006 Prius is 2 years old. The odometer is just over 25000 miles and I have never had any issues with the 12V battery or traction battery for that matter since day 1.

I routinely park at the airport for many days at a time and leave the car home on vacation for up to 3 weeks without running. I have never turned off the SKS smart key system since I bought the car although many say you should when leaving the car un-run for so long but I have never had any kind of battery failure!

It is my opinion that a properly charged 12V battery going dead after a few days is a sign of a pending battery failure, abnormal current drain like a light left on, or improper connection like corrision.

note: 2 year fuel average is 51.8 mpg! :bounce:Most of my driving is on a highway at 65mph. Winter avg is approx 49mpg and summer 53.8. Tires at 42/40 psi.

 

cmankat probably has it right. The "smart start" will discharge the battery after about two days of idle. I use my 2007 infrequently and keep it turned off and sometimes don't drive it for over a week. With it on, about two days max.

 

I just picked up a 12v battery today, $154. I have a VHF/UHF ham radio attached to it and when I turn the radio on it shows a volt meter for a few seconds.For some reason I always turn the radio on first and it has always been around 12.6v. Over the weekend it dropped to 9v and when I pushed the start button the radio shut down, too low a voltage, car startedfine. I knew it was time for a new battery.

They should have some sort of warning when it gets low instead of people getting stuck with a dead 12v battery.

 

There is a Diagnostic check on the car. Put car in ready, Hold info down, turn headlights on and off three times, go to menu-display- vehicle signal. One of the six items that show up is Acc Battery voltage. Mine is practically always 13.9 V. When sitting in the car listening to the radio, ham or otherwise, enjoying the AC, ALWAYS put car in the ready mode so the engine can charge the HV Bat and the HV Battery can charge the Accesory (12VDC) That small amount of gas you use is worth it. Also, if I think the cars going to be non-operational for a few days I force - charge the HV by putting it in drive and stepping in the accelerator until the HV is Green. Keep foot on Brake and apply footbrake. It takes about a minute. This really works!

 

TO OUR FINE MODERATOR: PATRICK WONG: Hi Pat, we may as well wear this subject out, my question is: when the vehicle is quiescient (Totally shut down, Parked) is there an automatic transfer of voltage from the HV to the 12V OR does this only occur in a power-up mode. ty andy

 

There is no transfer from the HV battery to the 12-volt when the car is shut down because the HV is physically disconnected. In fact, if you have the radio off when you push the start button, you will here some clicks coming from the back of the car which are the relays connecting the HV battery.

 

Thanks for the reply Larry. To continue this thread rather than start a new one, I'll make a comment that there is probably Extreme variances in the SOC and general condition of each and every 12VDC ( boot-up ) battery. Because of owner use or abuse, understanding of batteries ( especially this one ) Neglect at the docks and ignorance by the dealerships to bring the batteries up to thier ideal state....( before Sale! ). Including a definite lack of ability or desire to insure a known good battery. Including of course owners not being aware of its sensitivities. Because of all these factors it is impossible to lump this battery and its assorted problems into any ONE category. I would say at this point in time that Toyota has had plenty of time and knowledge to correct this very well known problem. Instead they allow the owner to find a problem and perhaps solve or not solve the problem at less than they would pay if they faced the problem squarely. Toyota, you make a great and revolutionary car, and I Thank-you, but you failed miserably with this puny boot-up battery.

 

And, we only hear from the members.

 

Perhaps, therein lies the very problem with the design. The 12V can discharge while parked, but cannot feed the puny battery from the HV (while parked).

 

That opens another can of worms, though. You'd then run the risk of draining the HV battery too. Although it has a vastly higher capacity, there are situations where this could happen -- you leave the headlights on while on vacation. You'd then really be hosed.

People have suggested a "self-jump" capability, which would let you engage the HV-to-12v inverter. The problem with this is that the Prius does checks on its systems before engaging the HV system which couldn't be done in this case.

Or Toyota could just use a standard-sized battery. I'm sure the reason they opted for the mini battery is to save weight.

 

Yes, it seems ironic that the Prius can be left unserviceable due to a failed 12V auxiliary battery, while the traction battery has plenty of power and is sitting there quietly.

It is also irritating that a replacement 12V battery costs ~$160 from the dealer considering its small capacity. However the AGM battery comes from Japan, not China so that might help to explain the high cost.

My HiHy also has a relatively small 12V battery located under the hood. It has the traditional liquid-acid design and even has a sight glass to assess electrolyte status in one cell.

I recall looking at the Ford Escape Hybrid and noting that it has a regular-size 12V battery; a good idea from the Ford engineering team.

Finally, I confirm Larry's comment that the 12V auxiliary battery will be charged only when the Prius is READY; as that is when the DC to DC converter can operate and keep the 12V bus at 13.8V.

 

What you refer to as a "mini battery" is no smaller than the battery in most small 4 cylinder cars these day and a small battery is used to save weight. Well that is the case with my Prius.
My 2004 Prius still has the factory fitted battery and there is no sign it is about to fail. There in lies the problem, Prius doesn't give any warning the battery is near failing. In your other car when the battery is getting weak the cranking speed drops, not so in a Prius. "Suddenly my battery failed" no it happened over 3 or 4 years, you only just realised it.

The battery size is fine, it may even be oversize for purpose.

 

standing charge for our 12v battery, put into service march 2005, is 12.2v.

also, since it's been brought up in this thread, any parts replaced under warranty can not be returned to the customer. this is partly for accountability on behalf of the technician and dealership (ie, to fight warranty fraud) and also so that toyota can study failure patterns.

 

Hi Andy,

Note that if you run this check when the Prius is READY, then what you are measuring is the output of the DC to DC converter which is regulated to be ~13.8V.

If you want to see the voltage produced by the 12V battery you should measure (using a digital voltmeter) after the car has been IG-OFF for an hour or more. 12.6V is considered to be fully-charged; 12.2V is half-charged. Battery voltage will drop in cold ambient temps.

 

The problem here is the steps required to make it work:

1. Power up ECUs
2. Power up system main relays

The 12V battery has to have enough charge to perform steps one and two - which pretty much is all that's needed to 'start the car'.

It's a chicken/egg scenario - to do the '12V recovery' step the 12V battery must have enough charge to turn the car on - well, we knew that already.

 

I have a question and I'm wondering if anyone has heard this or had a similar issue with Toyota and/or their Prius.
Dec. 29th my Prius died. It was towed in and the 12-volt battery was recharged. I've had no problems since. After a poor survey response, the mechanic who worked on the vehicle talked to me and said that in order for it not to happen again, I'd need to be sure to take a 20 minute drive on the freeway every weekend b/c the 6 miles (each day) I put it on it Monday thru Friday (+ weekend errands) is not enough to keep the 12-volt battery from discharging. He said it's common in winter especially b/c the 12-volt runs the heater in addition to the other computers and the draw on the 12-volt is (I'm paraphrasing) basically more than it can handle. He said it doesn't happen in the summer b/c the AC is run off another battery. He also stated that this can happen after the vehicle has sat for just 3-4 days, and he sees MANY cases of them not starting after not being driven for a week. He said this was something Toyota didn't tell people, but this is what he knows from his experience.
I immediately called the main Toyota 1-800 number and was told something completely different: that I certainly didn't need to take the car on a nice (and unneeded) 20 minute drive every weekend, that the heater doesn't draw from the 12-volt battery, and that you can leave the car for at least 3 weeks before the 12-volt battery becomes an issue.
My understanding is that I'm the ideal driver in that I have many short, in-town trips and that was confirmed by both of the people I spoke with today. The Toyota rep also told me to try to recreate the dead battery to figure out if it's a faulty battery or not.
Now, I don't know what to believe as these are completely opposite reponses from people who are both Toyota reps.
I bought the car b/c I love everything it stands for, but now I'm completely insecure in its' reliability and don't feel like I can trust Toyota at all.
Thanks for any responses.
~Amanda

 

The heater does not run from the 12V battery. All the 12V battery does is boot the computers and close a couple of power relays, after that all power is supplied from the HV system. The only exception is running lights and the radio without having the system in "Ready" mode.

The 12V battery on the Prius charges rather slowly. If you run it down it does take a few hours of being in Ready mode to charge it up. Your short drives should be enough unless the battery is getting weak or you leave a light on.

Tom